chem2 extra material for final

positive standard cell potential corresponds to a

spontaneous redox reaction

is gibbs free energy positive or negative for a spontaneous reaction

negative

is gibbs free energy positive or negative for a nonspontaneous reaction

positive

dry cell batteries

do not contain a large amount of water

zinc is anode, carbon rod is cathode

alkaline battery

employs half reactions that differ slightly in a basic medium

lead-acid storage batteries

consist of 6 electrochemical cells wired in series

fuel cells

need to be constantly replenished from an external source

electolysis

electrical current drives an otherwise nonspontaneous redox reaction

in electrochemical cells…

oxidation is an anode

reduction is at cathode

in voltaic cells…

anode has negative charge

cathode has positive charge

in electrolytic cells…

cathode is connected to negative terminal

anode is connected to positive terminal

overvoltage

an additional voltage that must be applied in order to get some nonspontaneous reactions to occur

radioactivity

the emission of subatomic particles or high energy electromagnetic radiation by the nuclei of certain atoms

types of radioactivity

alpha decay, beta decay, gamma ray emission, positron emission, electron capture

alpha decay

an unstable nucleus emits a particle composed of two protons and two neutrons

highest ionizing power but lowest penetrating power

mass will decrease by 4 and atomic number will decrease by 2

beta decay

an unstable nucleus emits an electron

atomic number will increase by one

gamma ray emission

a high energy photon called a gamma ray is emitted from a radioactive atom

lowest ionizing power but highest penetrating power

mass/atomic number is not changed

positron emission

an unstable nucleus emits a positron, which is the antiparticle of the electron

atomic number decreases by one

electron capture

a nucleus absorbs an electron from an inner orbital of its electron cloud

corrosion

the gradual oxidation of metals that are exposed to oxidizing agents in the enviorment

the sum of atomic numbers and sum of mass numbers on both sides of a nuclear equation must be ____

equal

ionizing power

the ability of radiation to ionize molecules and atoms

penetrating power

the ability to penetrate matter